Fixed linked formatting in markdown output.

Author: sideshowbarker

Makefile

@@ -14,5 +14,6 @@ README.md: index.html
 	    | $(PERL) $(PERLFLAGS) -pe 'undef $$/; s/(\s+\n)+/\n\n/g' \
 	    | $(PERL) $(PERLFLAGS) -pe 'undef $$/; s/(\n\n\n)+/\n/g' \
 	    | $(FMT) $(FMTFLAGS) \
-	    | $(PERL) $(PERLFLAGS) -pe 'undef $$/; s/ +(\[[0-9]+\]:)\n +/\n   $$1 /g' \
+	    | $(PERL) $(PERLFLAGS) -pe 'undef $$/; s/ +(\[[0-9]+\]:)\s+/\n   $$1 /g' \
+	    | $(PERL) $(PERLFLAGS) -pe 'undef $$/; s/(\n\n\n)+/\n\n/g' \
 	    | $(EXPAND) $(EXPANDFLAGS) > $@

README.md

@@ -4,8 +4,10 @@ The Nu Markup Checker is the backend behind [http://validator.nu][1],
 [http://html5.validator.nu][2], [http://validator.w3.org/nu/][3], and the HTML5
 facet of the [W3C Validator][4].
 
-   [1]: http://validator.nu [2]: http://html5.validator.nu
-   [3]: http://validator.w3.org/nu/ [4]: http://validator.w3.org
+   [1]: http://validator.nu
+   [2]: http://html5.validator.nu
+   [3]: http://validator.w3.org/nu/
+   [4]: http://validator.w3.org
 
 The source code for the Nu Markup Checker is contained in [a number of
 repositories hosted at github][5].